1. Field of the Invention
The invention relates, generally, to pneumatic valve assemblies and, more specifically, to a pneumatic valve having a pilot valve integrated into a single valve body.
2. Description of the Related Art
Pilot operated pneumatic valves are well known in the art for controlling the flow of pressurized air to and from various pneumatically actuated devices such as press clutches, air brakes, air cylinders or any other pneumatic device or application requiring precise control of operating air. More specifically, two-way, three-way and four-way pilot operated valve assemblies are commonly employed in these environments. Such valves typically include a main valve body with a valve member movably supported within a valve bore in response to air pressure which is directed by a separate pilot valve to one or alternating ends of the valve member. A solenoid actuates the pilot valve to one predetermined position. A return spring or another pilot valve is employed to bias the valve member back to a known position.
Valve assemblies of this type known in the related art typically include a main valve body to which is separately mounted a pilot valve body using fasteners. Valves of this type are employed in a wide variety of manufacturing environments where a high flow rate and very fast response time are desired. As the technology for these valves has advanced, there has been an increase in the demand for smaller valves which are used in tight spaces. Over the years, there have been a number of improvements in this general field which have facilitated high flow rates and fast response times in relatively small valves. Still, there remains a need in the art for even faster and smaller valves. However, the common arrangement wherein a pilot valve is mounted to a main valve has become a design barrier which has affected the size and speed of such valves.